With system, you get the exit status of the processed command, whereas with qx (or "backticks `...`, which are the same thing as qx) you get the "collected standard output" of the command.

Please look at perlop, specifically the section titled "qx/STRING/".  You'll see that qx is the command to use when you need to assign to the output from your system command.

With the system command, on the other hand, you care more about the side-effects of running the command (in your case, the wget to fetch webpages), and in the end, only want to know whether the command succeeded or failed.

As for your "OK" versus "Server Error" status messages -- sorry, but I don't know much about wget.  Try doing a man page on it, or googling for documentation, and see if there's a verbose flag or something that will present a more detailed failure message.

Looks like wget is putting the response code into STDERR. I did this

$response = `wget --spider -nv $url 2>&1`;
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As for the varying return codes, it probably means that the server you're hitting is not able to respond properly everytime. Maybe it's overloaded, or purposely throttling you. Could be many things.

Thank you! the 2>&1 did the trick for me!

#!/usr/bin/perl
use warnings;
use strict;
use IPC::Open3;
use IO::Select;


my $pid = open3(0, \*READ,\*ERROR,"wget --spider -nv  http://zentara.n
+et");

my $sel = new IO::Select();

$sel->add(\*READ);
$sel->add(\*ERROR);

my($error,$answer)=('','');

 foreach my $h ($sel->can_read)
 {
   my $buf = '';
   if ($h eq \*ERROR)
   {
     sysread(ERROR,$buf,4096);
     if($buf){print "ERROR-> $buf\n"}
   }
   else
   {
     sysread(READ,$buf,4096);
     if($buf){print "response->$buf\n"}
   }
 }

waitpid($pid, 1);
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#!/usr/bin/perl 
use warnings;
use strict;
use IPC::Open3;

$|=1;

my $pid=open3(\*IN,\*OUT,\*ERR,'/bin/bash');

my $url = 'wget --spider -nv  http://zentara.net';

# setup a while loop here and feed it urls  
# while(@urls){

print IN "$url\n";
my $buf = '';
sysread(ERR,$buf,4096);
if($buf){print "ERROR-> $buf\n"}

sysread(OUT,$buf,4096);
if($buf){print "response->$buf\n"}

#}

waitpid($pid, 1);
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In a word, "No". Never use accent grave quotes like this...

If you insist on using them, please see "Re: Specifying a shell for use with Backticks"

Using one of the alternate HTTP modules as well should get you very high speed indeed.

As I previously mentioned... you want IPC::Run or IPC::Open3...

You do not want to use system here either. Well ok, you CAN use system in "list mode" here to avoid spawning a shell, but this is NOT what zentara showed you, that approach is unsafe.

Using "backticks" (otherwise properly known as "accent grave" is deathly unsafe, and you should never use anything of the sort. From the pod:

IPC::Open3, open3 - open a process for reading, writing, and error handling

Also, you should be using one of the standard LWP modules here, and catching the response codes that come back, instead of relying on a userland binary (which can easily be faked, opening a hole in your system).

If you don't value the security of the system, then go ahead and implement the unsafe, incorrect approach.